Low-Cost Multichemistry Battery Chargers
Typical Operating Characteristics (continued)
(Circuit of Figure 1, V
= 20V, T = +25°C, unless otherwise noted.)
A
DCIN
LINE-TRANSIENT RESPONSE
LDO LOAD REGULATION
LDO LINE REGULATION
MAX1908 toc04
0
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
-0.7
-0.8
-0.9
-1.0
0.05
0.04
0.03
0.02
0.01
0
V
DCIN
I
V
= 0
LDO
10V/div
= 5.4V
LDO
V
BATT
500mV/div
-0.01
-0.02
-0.03
-0.04
-0.05
INDUCTOR
CURRENT
500mA/div
V
LDO
= 5.4V
10ms/div
0
1
2
3
4
5
6
7
8
9
10
8
10 12 14 16 18 20 22 24 26 28
(V)
ICTL = LDO
VCTL = LDO
ICHARGE = 3A
LDO CURRENT (mA)
V
IN
LINE STEP 18.5V TO 27.5V
REF VOLTAGE LOAD REGULATION
REF VOLTAGE ERROR vs. TEMPERATURE
EFFICIENCY vs. CHARGE CURRENT
0
-0.01
-0.02
-0.03
-0.04
-0.05
-0.06
-0.07
-0.08
-0.09
-0.10
0.10
0.08
0.06
0.04
0.02
0
100
90
80
V
BATT
= 16V
70
60
V
BATT
= 12V
50
40
V
BATT
= 8V
-0.02
-0.04
-0.06
-0.08
-0.10
30
20
10
0
0
100
200
300
400
500
-40
-15
10
35
60
85
0.01
0.1
1
10
REF CURRENT (µA)
TEMPERATURE (°C)
CHARGE CURRENT (A)
FREQUENCY vs. V - V
BATT VOLTAGE ERROR vs. VCTL
OUTPUT V/I CHARACTERISTICS
IN
BATT
0.5
0.4
0.08
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0
500
450
400
350
300
250
200
150
100
50
2 CELLS
3 CELLS
3 CELLS
0.3
0.2
4 CELLS
0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
4 CELLS
I
= 3A
CHARGE
4 CELLS
REFIN = 3.3V
NO LOAD
VCTL = ICTL = LDO
0
1.0
0
2
4
6
8
10 12 14 16 18 20 22
0
1
2
3
4
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
VCTL/REFIN (%)
(V - V ) (V)
BATT CURRENT (A)
IN
BATT
_______________________________________________________________________________________
9
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
